University spokesman Dan Mogulof said the explosion, which caused several minor injuries, caused the power outage, which disrupted evening activities Monday, the San Francisco Chronicle reported.
One person was taken to a hospital with minor injuries as a result of the blast and several others were treated at the scene for minor burns, Mogulof said.
Mogulof said authorities were investigating whether a copper theft last week on campus led to the explosion and outage.
"The damage that could be seen and assessed was repaired over the weekend, but it now appears that the damage caused by the unknown vandals may have been far more extensive and may have been the cause of what happened," he said.
The power outage trapped about 20 people in elevators around campus for several hours, Mogulof said.
Evening classes were canceled and labs were closed. Many of the school's dormitories were without electricity Monday.